1. Field
Examples relate to an etchant, a method of forming a gate insulation layer using the etchant and a method of manufacturing a semiconductor device using the etchant. More particularly, examples relate to an etchant that reduces damage to the gate insulation layer, a method of forming the gate insulation layer using the etchant and a method of manufacturing a semiconductor device using the etchant.
2. Description of the Related Art
As the degree of integration of semiconductor devices increases, a gate electrode of the semiconductor device has been downsized and a channel region under the gate electrode has been also shortened. Thus, the gate insulation layer in recent semiconductor devices tends to be formed to a small thickness so as to increase the capacitance between the gate electrode and the channel and to improve operation characteristics of transistors. However, when the gate insulation layer comprises conventional materials such as silicon oxide and silicon oxynitride, the thickness reduction of the gate insulation layer can cause electric failures and deterioration of the reliability of the gate insulation layer. That is, when a silicon oxide layer or a silicon oxynitride layer is formed to a small thickness as the gate insulation layer, direct tunneling currents are increased through the gate insulation layer and thus a leakage current is frequently generated between the gate electrode and the channel under the gate electrode. For these reasons, intensive research has been conducted on dielectric layers having a high dielectric constant which can be used in place of the conventional silicon oxide layer or the silicon oxynitride layer.